Everyday Proportions

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Everyday Proportions
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Proportions can be useful for.
Map reading
Recipe conversions
Scale Models
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MapsThe distance between two cities is 3 ½ cm.
Using the map scale, what is the actual distance
between the two cities?
Step One- Set up your proportion. Make sure you
have the same measurement across from one
another. cm cm ½ 3 ½
miles miles 10
x


Step Two Find your cross products
.5 3.5 10 x
.5 x 35

Step Three Divide .5 x 35
.5 .5 x
70 miles
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RecipesA chocolate chip cookie recipe makes 48
cookies. One of the ingredients is ¾ cup of
sugar. If I wanted to make 144 cookies, how much
sugar would I need?
Step One- Set up your proportion. Make sure you
have the same measurement across from one
another. sugar sugar 3/4 x
cookies cookies 48 144


Step Two Find your cross products
.75 x 48 144
48x 108

Step Three Divide 48 x 108
48 48 x
2 ¼ cups of sugar
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Scale ModelsOn a model car, the door is 2in
long. If the scale is 124 ( 1/24 of the actual
size of the car), how long is the actual door?
Step One- Set up your proportion. Make sure you
have the same measurement across from one
another. model model 1 2
actual actual 24 x


Step Two Find your cross products
1 2 24 x
1x 48

Step Three Divide 1 x 48
1 1 x 48
inches
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A model jet has a scale of 3 in. 8 feet. If the
model has a wingspan of 9 inches, what is the
actual wingspan of the jet?
in. model in. model 3 9
ft. actual ft.actual 8 x


3 9 8
x 3x 72

3 x 72 3
3 x 24 feet
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A blueprint for Mrs. McFerrins new living room
has a scale of ¼ inch equals 15 feet. If the
blueprint measures the new room to be 3 ¼ inches,
how long is the actual room?
blueprint in. blueprint in. 1/4 3 1/4
actual ft. actual ft. 15
x


.25 3.25 15
x .25x 48.75

.25 x 48.75
.25 .25 x 195 feet
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On a roadmap of Florida, the scale was ½ cm
represents 50 miles. If Khadijah measured a
distance between two cities to be 5 ½ cm, what is
the actual distance?
cm. cm. ½ 5 ½
miles miles 50 x


.5 5.5 50
x .5x 275

.5 x 275
.5 .5 x 550miles
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A model ship is built to the scale of 2
centimeter 7 meters. The width of the model is
12 centimeters. What is the actual width of the
ship?
cm. model cm. model 2 12
m. actual m.actual 7 x


2 12 7
x 2x 84

2 x 84 2
2 x 42 meters
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Jacob wants to use a brownie recipe that makes 48
brownies, but he wants to make 36 brownies
instead. If the original recipe calls for 3 cups
of butter, how much will he have to use in the
new recipe?
butter butter 3 x
brownies brownies 48 36


3 x 48
36 48x 108

48 x 108
48 48 x 2 ¼ cups of
butter
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Justin wants to build a scale model of a 150
meter building in Richmond. If he wants to use a
scale of 1.5 centimeters 5 meter. How tall will
his model be?
model(cm.) model(cm.) 1.5 x
actual(m.) actual(m.) 5
150


1.5 x 5
150 5x 225

5 x 225
5 5 x 45cm. tall